FAA Study: Air Traffic Controllers' Schedules Can Lead To Fatigue : The Two-WayControllers who were closely monitored averaged 5.8 hours of sleep a day during the workweek. The number of hours dropped to 3.25 ahead of midnight shifts.

FAA Study: Air Traffic Controllers' Schedules Can Lead To Fatigue

Air traffic controllers' work schedules can lead to chronic fatigue, according to a study conducted by NASA researchers for the Federal Aviation Administration that was completed in December 2012 and published online Monday.

The Associated Press, which first reported on the findings, says the study came about after the National Transportation Safety Board made a recommendation to the FAA and the National Air Traffic Controllers Association that they change controllers' schedules to provide more time to sleep.

The news service adds:

"In the field study, researchers concentrated on controllers who worked a schedule known as the 'rattler' in which controllers squeeze five eight-hour shifts into four 24-hour periods by cutting the turnaround time between shifts to as little as eight hours. Some controllers like the schedule because it gives them a 3-day weekend.

"Controllers participating in the study wore a wrist device that recorded when they were asleep. They also kept logs of their sleep, and were administered alertness tests several times per work shift."

The AP noted that "[FAA] officials had declined to furnish a copy [of the report] despite repeated requests over the past three months, including a Freedom of Information Act filing."

Here are a few key things to know from the 270-page study:

3,268 people took an online survey of fatigue factors, and more than 200 participated in a field study using wrist monitors.

On average, controllers in the field study got 5.8 hours of sleep a day during the workweek, but the number of hours dropped to 3.25 for controllers working midnight shifts.

70 percent of those working midnight shifts said they had caught themselves "about to doze off" while working.

18 percent of respondents said they had been involved in an operational error at work, and 56 percent of those people involved felt that their own fatigue had been a contributing factor.